Problem: The arithmetic sequence $(a_i)$ is defined by the formula: $a_1 = -10$ $a_i = a_{i-1} + 4$ What is $a_{2}$, the second term in the sequence?
Explanation: From the given formula, we can see that the first term of the sequence is $-10$ and the common difference is $4$ The second term is simply the first term plus the common difference. Therefore, the second term is equal to $a_2 = a_1 + 4 = -10 + 4 = -6$.